title: Electronic spectroscopy of diatomic VC.
abstract: Resonant two-photon ionization spectroscopy has been applied to diatomic VC, providing the first optical spectrum of this molecule. The ground state is determined to be a (2)Δ3/2 state that arises from the 1σ(2)1π(4)2σ(2)1δ(1) configuration. The r0" ground-state bond length is 1.6167(3) Å. The manifold of excited vibronic states in the visible portion of the spectrum is quite dense, but two possible vibrational progressions have been identified. It is noted that VC joins CrC, NbC, and MoC as species in which the metal ns-based 3σ orbital is unoccupied, resulting in large dipole moments in the ground states of these molecules. In the corresponding 5d metal carbides, however, the 3σ orbital is occupied, leading to different ground electronic states of the 5d congeners, TaC and WC.
authors.affiliation: Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States.
authors.forename: Olha
authors.initials: O
authors.lastname: Krechkivska
authors.forename: Michael D
authors.initials: MD
authors.lastname: Morse